CapabilityMapper

libs/providers/src/lib/capability-mapper.ts

Purpose

CapabilityMapper validates that a set of messages (including resource attachments) is compatible with a model's declared input/output capabilities before dispatching to a provider. It is the TypeScript-layer guard between the unified ProviderMessage[] format and per-provider wire formats.

Why TypeScript, not the database

The database stores ai.models.input_modalities text[] and output_modalities text[] as the source of truth. But validation happens in TypeScript because:

1. Feedback loop: Validation errors must reach the UI or CLI immediately — before any API call. A DB CHECK constraint can't do this.
2. No round-trip cost: The validation is pure logic on already-fetched data.
3. Type safety: TypeScript's type system enforces ContentPart union exhaustiveness.

Usage

import { capabilityMapper } from '@lenserfight/providers'

const errors = capabilityMapper.validate(messages, {
  inputModalities: model.input_modalities,
  outputModalities: model.output_modalities,
  supportsTools: false,
  supportsJsonSchema: false,
  supportsStreaming: true,
})

if (errors.length > 0) {
  // Surface errors to UI — do NOT dispatch
}

Provider capability matrix

Provider	Text in	Image in	Document in	Audio in	Video in	Text out	Image out	Video out
OpenAI (gpt-4o)	✓	✓	—	—	—	✓	—	—
Anthropic (Claude)	✓	✓	✓	—	—	✓	—	—
Google (Gemini)	✓	✓	✓	✓	✓	✓	✓	✓
Mistral	✓	✓	—	—	—	✓	—	—
Ollama	✓	✓ (base64)	—	—	—	✓	—	—
FAL	—	—	—	—	—	—	✓ (Flux)	✓

These values are stored as input_modalities / output_modalities TEXT[] on ai.models. Backfilled by migration 45 from existing supports_vision boolean.

Adding a new provider

1. Create libs/providers/src/lib/<provider>.ts implementing ProviderAdapter (and optionally StreamingProviderAdapter).
2. Map ContentPart types to the provider's wire format in transformRequest.
3. Register in libs/providers/src/index.ts under ADAPTERS / STREAM_ADAPTERS.
4. Add the provider's model rows to ai.models with correct input_modalities / output_modalities.
5. No changes to CapabilityMapper needed — it reads from model.inputModalities[].

ContentPart indirection layer

The ContentPart union (libs/providers/src/lib/types.ts) is the abstraction between callers and per-provider wire formats:

type ContentPart =
  | { type: 'text'; text: string }
  | { type: 'image'; url: string; mimeType?: string; detail?: 'low' | 'high' }
  | { type: 'document'; url: string; mimeType: string; name?: string }
  | { type: 'audio'; url: string; mimeType: string }
  | { type: 'video'; url: string; mimeType: string }

Each provider adapter maps this to its own format:

• OpenAI: image_url content block
• Anthropic: image / document source block
• Gemini: fileData inline part
• Ollama: images: [base64] sibling field (images only)

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Part of Platform & API Reference